Phase field modelling voids nucleation and growth in binary systems

We present a comprehensive study of voids formation, nucleation and growth in a prototype model of binary alloys subjected to irradiation by using a combined approach based on phase field and rate theories. It is shown that voids formation is caused by interaction of irradiation-produced vacancies through elastic deformation of a lattice and vacancy coupling with composition field of the alloy. Phase diagrams illustrating the formation of states related to solid solution, phase decomposition, and patterning are obtained. Formation of voids from supersaturated ensemble of vacancies is accompanied by composition rearrangement of alloy components. It was found that elastic inhomogeneity leading to the formation of anisotropic precipitates in an initially prepared binary alloy results in the formation of a void super-lattice under irradiation. It was shown that voids nucleate and grow with dose according to diffusion controlled precipitation processes, where universal dynamics of voids growth is revealed. Estimations of main quantitative and statistical characteristics of voids by using material parameters relevant to most of alloys and steels give good agreement with experimental observations.Comment: 21 pages, 10 figure

WHAT RESULTS IN TENDON AND MUSCLE TISSUES OF THE ROTATOR CUFF FROM FULL-THICKNESS TEARS: DATA OF MRI, ARTHROSCOPY AND HISTOLOGY

Full-thickness rotator cuff tears - is abundant injury which leads to the expressed pain syndrome and functional violation of the top extremity. At making decision about necessary of surgery, MRI is the important source of information about the injury The purpose: to determine the qualitative and quantitative indicators of degenerative-dystrophic changes in muscular and tendinous parts of the rotator cuff. based on a combined MRI, arthroscopic and histological diagnostics of full-thickness rupture of shoulder cuff Methods: We have examined 28 patients with full-thickness rotator cuff tears. MRI of damaged joint to all patients before an operation was performed. Thereafter an arthroscopy was performed and intraoperative biopsy of the muscular and tendinous parts of the rotator cuff, with following histological examination. Results: It was found that at small full-thickness rotator cuff tears the intensity of degenerative changes in muscular and tendinous tissue was lower, so these tears are the most promising for all kinds of treatment. At medium and big tears intensity of degenerative changes in the tissues begins to prevail over productive inflammation and it limits to the ability of conservative treatment and increases the risk of unsuccessful outcomes of arthroscopic reconstruction. Conclusions: In this regard, it is necessary to search biological decisions, which complement the stage of arthroscopic reconstruction of the rotator cuff

Deposition of chromium nitride coatings from vacuum arc plasma in increased nitrogen pressure

The application of protective coatings on metal materials is the effective way to improve their durability. Chromium nitride coatings are applied mainly on tools due to good resistivity to oxidation compared to other metal nitride coatings and good wear resistance. Some characteristics of the coatings deposited in fixed position in regard of chromium cathode on the samples parallel directed to it and the other arranged opposite in the nitrogen pressure ranged from 0.5 to 3.0 Pa are investigated.Применение защитных покрытий на металлических материалах является эффективным способом улучшения их прочности. Покрытия из нитрида хрома применяются в основном на инструменте благодаря хорошему сопротивлению окислению, по сравнению с другими нитридными покрытиями, и хорошей износостойкости. Были исследованы некоторые характеристики покрытий, осажденных в фиксированном положении на лицевую и обратную стороны образцов, установленных в плоскости, параллельной по отношению к хромовому катоду, в диапазоне давлений азота от 0,5 до 3,0 Па.Застосування захисних покриттів на металевих матеріалах є ефективним способом поліпшення їх міцності. Покриття з нітриду хрому застосовуються в основному на інструменті завдяки гарному опору окисленню, в порівнянні з іншими нітридними покриттями та добрій зносостійкості. Були досліджені деякі характеристики покриттів, осаджених у фіксованому положенні на лицьову і зворотну сторони зразків, встановлених в площині, паралельній по відношенню до хромового катода, в діапазоні тисків азоту від 0,5 до 3,0 Па

Geometry and symmetries of multi-particle systems

The quantum dynamical evolution of atomic and molecular aggregates, from their compact to their fragmented states, is parametrized by a single collective radial parameter. Treating all the remaining particle coordinates in d dimensions democratically, as a set of angles orthogonal to this collective radius or by equivalent variables, bypasses all independent-particle approximations. The invariance of the total kinetic energy under arbitrary d-dimensional transformations which preserve the radial parameter gives rise to novel quantum numbers and ladder operators interconnecting its eigenstates at each value of the radial parameter. We develop the systematics and technology of this approach, introducing the relevant mathematics tutorially, by analogy to the familiar theory of angular momentum in three dimensions. The angular basis functions so obtained are treated in a manifestly coordinate-free manner, thus serving as a flexible generalized basis for carrying out detailed studies of wavefunction evolution in multi-particle systems.Comment: 37 pages, 2 eps figure

Stereo sensitivity of exchange interactions in Ni^II and Cu^II heterospin complexes with 5-formylpyrrolyl-substituted nitroxides

© 2016, Springer Science+Business Media New York.5-Formylpyrrolyl-substituted nitronyl and imino nitroxide radicals HL1 and HL2 were synthesized. Their solid phases are formed by packing pairs of the molecules. In the {HL1..HL1} pairs, the dominant interaction is the ferromagnetic exchange with J/kB = 8.8 K (Hamiltonian H= 2 J(s1→ · s2→)). The ferromagnetic exchange occurs also in the heterospin molecules [Ni(L1)2], [Cu(L1)2], and [Ni(L2)2(MeOH)2]. In the complexes [Ni(L1)2] and [Cu(L1)2], a small change in the mutual orientation of the coordinated ligands has a considerable effect on the value and the sign of the energy of exchange interactions between the unpaired electrons of the metal ion and paramagnetic ligands

ЗАСТОСУВАННЯ ІННОВАЦІЙНИХ ТЕХНОЛОГІЙ ЯК ЗАПОРУКА ПІДВИЩЕННЯ ЕФЕКТИВНОСТІ ТА ЯКОСТІ НАВЧАННЯ У ВИЩІЙ ШКОЛІ

This article aims to characterize an integration of the process of education to European area, some current problems of the interactive teaching methods have been analyzed including multimedia technologies and computer testing. In terms of the rapid development of the society teachers are facing the new challenges of the scientific and methodical approaches to professional disciplines. The modern approach involves a presentation of the new materials allowing for the large volume of educational information at a certain period of time and effective organization of the process of education and objective evaluation of the results.У статті, з метою інтеграції навчального процесу до Європейського простору, проаналізовані деякі сучасні застосування інтерактивних методів навчання, зокрема мультимедійних технологій та комп’ютерного тестування. В умовах інформатизації суспільства і бурхливого розвитку техніки перед викладачами постають нові завдання до організації науково-методичного підходу викладання фахових дисциплін. Сучасний підхід передбачає презентацію нового матеріалу при великому обсязі інформації за певний час, ефективну організацію навчального процесу та об’єктивного оцінювання його результатів

Investigation of contact deformation and wear characteristics of discrete track recording media

The even semester 2014/2015 Technical Information Engineering University of Semarang (USM) has been running the Competency Based Curriculum (CBC) in the management of learning. Conversions that occur in some subjects at an increase in scheduled meetings in the classroom or in the laboratory. Computer Networks is one of the subjects who experienced a conversion. In the curriculum in 2008, Computer Networking has a number of credits 3. From the 2 credits 3 credits are for credits 1 credits for theory and practical credits. While at the CBC in 2013, Computer Networking has 4 credits, with details of 2 credits 2 credits theory and practicum. As lecture and instructor Computer Network, researchers interested in studying the effect of applying the CBC in 2013 in the subje ct of Computer Network. Does the addition of meeting practical and theoretical material renewal in accordance with the expected competencies?. Researchers tried applying the CBC in 2013 by conducting action research. Implementation of the research was conducted during an ongoing lecture that even semester 2015/2016. The results of the study during the first half of researchers will compare with the achievements that never existed when the old curriculum still in use. The goals of this research is, subjects in the Computer Network has always been one of the subjects that the content of the material and its application in the lab was able to follow the needs of the workforc

Tribological properties of vacuum arc Cr-O-N coatings in macro- and microscale

In this paper the tribological properties of Cr-O-N coatings deposited using vacuum arc plasma flux in macro- (sphere-on-disc test) and microscale (AFM-atomic force microscopy) are investigated. It was found that the specific wear rate determined in AFM measurements (micro scale) is approximately 2 orders higher than the macroscale. This is probably due to much higher Hertzian contact stress.Исследовались трибологические свойства Cr-O-N-покрытий, осаждённых из потока вакуумно-дуговой плазмы на макро- (тест сфера-на-диске) и микроуровне (AСM-атомно-силовая микроскопия). Было установлено, что удельная скорость износа в измерениях AСM (микроуровень) примерно на 2 порядка выше, чем в макромасштабе. Это, вероятно, связано с гораздо более высокими контактными напряжениями.Досліджувалися трибологічні властивості Cr-O-N-покриттів, осаджених з потоку вакуумно-дугової плазми на макро- (тест сфера-на-диску) і мікрорівні (AСM-атомно-силова мікроскопія). Було встановлено, що питома швидкість зносу у вимірюваннях AСM (мікрорівень) приблизно на 2 порядки вище, ніж в макромасштабі. Це, ймовірно, пов'язано з набагато більш високими контактними напруженнями